The United States Occupation Safety and Health Administration (OSHA) requires chains and certain heavy equipment used in industrial settings to carry an identifying tag. The tag is stamped or engraved with identifying information, such as a serial number, model number, and other characteristics. Standard descriptive and/or warning text is engraved, molded, or embossed in the tag. Such tags are often made of steel or other durable metal.
Unfortunately, these industrial identification tags often deform in the face of typical industrial use. For example, when a chain is dragged behind a vehicle over the road, run over, or struck against a metal structure, or even where it might be subjected to intentional stress such as shot peening, the tags on these chains are often deformed beyond recognition (certainly beyond accurate, useful reading of data on its surface). Then, in order to comply with regulations, the tag must be replaced before the chain or equipment is used again.
There is a need, therefore, for more durable tags from which the necessary information can be read even after exposure to sometimes extreme stresses in industrial environments.
In addition, maintenance and use of industrial tags requires regular checking for the presence and proper condition of the tags. There is, therefore, also a need for convenient methods for checking industrial tags for function and legibility.